There is conventionally known a liquid-level detection device that detects a level of the liquid surface by measurement of a rotation angle of a rotatable body that rotates in accordance with a liquid surface of liquid. As a kind of such a liquid-level detection device, a configuration disclosed in, for example, Patent Document 1 includes a magnet holder that holds a pair of magnets, and a housing that rotatably supports the magnet holder by a supporting shaft in which a Hall IC is embedded.
In the above-described configuration, the density of magnetic flux passing through the Hall IC changes according to the rotation of the magnet holder that holds the pair of magnets. Accordingly, by measurement of a rotation angle of the magnet holder based on the output from the Hall IC, the liquid-level detection device can detect a level of a surface of liquid stored in a container.